﻿using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace FileThief
{
    public static class Util
    {
        public static decimal? ToDecimalOrNull(this string x)
        {
            decimal y;
            return decimal.TryParse(x, out y) ? (decimal?)y : null;
        }

        public static bool? ToBoolOrNull(this string x)
        {
            bool y;
            return bool.TryParse(x, out y) ? (bool?)y : null;
        }

        public static int? ToIntOrNull(this string x)
        {
            int y;
            return int.TryParse(x, out y) ? (int?)y : null;
        }

        public static int ToInt(this string x)
        {
            int y;
            return int.TryParse(x, out y) ? y : 0;
        }

        public static long ToLong(this string x)
        {
            long y;
            return long.TryParse(x, out y) ? y : 0;
        }


        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <param name="encryptKey">加密密钥,要求为8位</param>
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
        public static string EncryptDES(string encryptString)
        {
            string encryptKey = "xmut3410";
            string keys = "_21#604_";

            try
            {
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Encoding.UTF8.GetBytes(keys.Substring(0, 8));
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());
            }
            catch
            {
                return encryptString;
            }
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
        public static string DecryptDES(string decryptString)
        {
            try
            {
                string decryptKey = "xmut3410";
                string keys = "_21#604_";

                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0, 8));
                byte[] rgbIV = Encoding.UTF8.GetBytes(keys.Substring(0, 8));
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
            {
                return decryptString;
            }
        }

    }

}
